A semiconductor light emitting device such as a light emitting diode (LED) is a device including a light emitting material, in which energy generated through electron-hole recombination in semiconductor junction parts is converted into light to be emitted therefrom. LEDs are commonly employed as light sources in illumination devices, display devices, and the like, and the development of LEDs has been accelerated.
In particular, the development and employment of gallium nitride (GaN)-based LEDs has recently increased, and mobile keypads, vehicle turn signal lamps, camera flashes, and the like, using such a gallium nitride-based LED, have been commercialized, and, in line with this, the development of general illumination devices using LEDs has accelerated. Like the products to which they are applied, such as a backlight unit of a large TV, a headlamp of a vehicle, a general illumination device, and the like, the purposes of LEDs are gradually moving from small portable products toward large-sized products having high output and high efficiency, and pertinent products require light sources that can support unit required characteristics thereof.
As the purposes of LEDs are broadened and LEDs are mass-produced, the recycling of semiconductor growth substrates used for manufacturing LEDs has emerged as an issue.